ROT13 Encoder Decoder
ROT13 encode and decode — the self-reversing letter cipher.
How to use ROT13 Encoder Decoder
- Type or paste your text.
- Read the ROT13 output — letters shifted 13, numbers/punctuation untouched.
- Decode the same way — paste ROT13'd text and it returns to plain (ROT13 is its own inverse).
- Use only for casual hiding — spoilers and puzzles, never real secrets.
What is ROT13 Encoder Decoder?
ROT13 shifts every letter 13 places through the alphabet — A↔N, B↔O, and so on. Its charming property: because 13 is exactly half of 26, applying ROT13 twice returns the original, so the same operation both encodes and decodes. "Hello" becomes "Uryyb"; ROT13 "Uryyb" and you're back to "Hello".
ROT13 is emphatically NOT encryption — it's trivially reversible obfuscation, the digital equivalent of writing upside-down. Its purpose is hiding text from casual accidental reading, not from anyone trying: spoilers, puzzle answers, joke punchlines, mildly offensive content you want people to opt into seeing.
About the ROT13 Encoder Decoder
Type or paste text and get its ROT13 version instantly — the same box decodes ROT13 back to plain text (it's self-inverse).
Where ROT13 lives: spoiler and answer hiding in forums, newsgroups (its original Usenet home) and comment threads — post the ROT13'd spoiler, and only readers who deliberately decode it see it; puzzle and CTF challenges as a gentle first layer; obscuring hints in games and ARGs; and a programming teaching classic — implementing ROT13 is a rite-of-passage string exercise. Numbers and punctuation pass through unchanged (ROT13 only touches letters).
The security reminder that always accompanies ROT13: never use it to protect anything real — passwords, secrets, private data. It stops accidental reading and nothing more. For actual concealment, encryption (AES) is the tool; for authentication, HMAC; for password storage, bcrypt. ROT13 is a social convention for "look away unless you want to know", implemented in the alphabet.